Internal combustion engines are typically each include an engine body, e.g. engine block and head, that require cooling by an engine coolant to remove excessive heat. Many engines also include fuel injectors mounted in respective injector mounting bores and including nozzle assemblies used to inject fuel into the engine cylinders for combustion. The fuel injectors, including the nozzle assemblies, are exposed to very high temperatures and thus require cooling. The physical separation of engine coolant and injection fuel in the vicinity of the injector in the engine cylinder head is challenging from a manufacturing/assembly perspective and may add to reliability issues.